Spark-plug.



G. T. SIMMONS.

SPARK PLUG. APPLICATION FILED OCT. 19. 1914..

Patented Dec. 7, 1915.

Z l/VVE/VTOR Allarney GEORGE '1. SIMMONS, 0F JANESVILLE, WISCONSIN.

SPARK-PLUG.

Specification of Letters Patent.

Patented Dec. 7, 1915.

Application filed October 19, 1914. Serial No. 867,396.

To all whom it may concern: I

Be it\known that I, GEORGE T. SiMMoNs, a citizen of the United States, and a resident of J anesville, in the county of Rock and State of Wisconsin, have invented certain new and useful Improvements in Spark- Plugs; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in spark plugs for internal combustion engines.

Considerable difliculty and annoyance have been occasioned with spark plugs as heretofore constructed, on account of the fouling of the plugs by an accumulation of oil and carbon deposit on the sparking points, resulting in the occurrence of misfire and the consequent inefficient operation of the engine.

When a cylinder becomes worn and scored or the piston is worn or its rings are broken, a greater amount of oil than is needed finds its Way past the piston and rings. This oil follows along the wall of the compression chamber and is spread by compression and heat over all of the interior of the compression chamber and into the interior of the plugs, resulting in disabling or reducing the efficiency to a greater or less extent, as heretofore mentioned.

The object of my present invention is to so construct the shell of a spark plug, that the oil will be prevented from entering the plug or reaching the sparking points thereof, and thus preventing said sparking points from fouling.

With this and other objects in view, the invention consists in certain novel features of construction as hereinafter described and pointed out in the claims.

In' the accompanying drawings, Figure 1 shows a portion of an engine cylinder showing the application of a spark plug embody ing my invention; and Figs. 2, 3, 4t, 5, 6 and 7 show various modifications.

1 represents a portion of the cylinder of an internal combustion engine; 2 the piston thereof, and 3 indicates one embodiment of my improved spark plug.

The spark plug comprises a body orcore member 4. of porcelain or other suitable nonconducting material and carries the conductor 5 which constitutes one of the plug terminals. The porcelain body or core is secured in a metallic shell; or casing 6 and the latter is made with a threaded portion 7 to screw through the plug opening of the cylinder.

The shell 6 is made with a comparatively thin extension 8 which depends from the threaded portion of the shell and projects well into the combustion chamber of the cylinder. In the form of the invention shown in Fig. 1, the said depending or apron portion of the shellis made in conical form with an opening 9 at its apex, through which the conductor 5 passes and constitutes one of the sparking terminals,the other sparking terminal being formed by or on the wall of said opening 9. The depending apron or extension 8 of the shell 6 is made with a plurality of depending concentric annular flanges 10 forming the walls of similarly-shaped grooves 11. From the above, it will be seen that the depending extension of the shell comprises a plurality of thin walls separated by grooves, over which oil would have to travel to reach the sparking terminals of the plug or to enter the latter. During the operation of the engine, these walls become heated to such a degree as to flash or burn the oil as it attempts to pass over them, and before it can enter the plug or reach the sparking terminals,thus protecting said contacts from accumulation of oil or carbon deposit and thereby obviating the difiiculties heretofore encountered with other plugs in which the sparking terminals are exposed to such accumulations.

Instead of forming the conical extension of the shell, with a plurality of annular flanges concentric with the longitudinal axis of the plug, a single annular flange 12 as shown in Fig. 2 might be employed and good results obtained,the space between this flange and the conical extension of the shell forming a groove 13 corresponding in function with the grooves 11 in the form of the invention shown in Fig. 1.

In the form of the invention shown in Fig. 3, tapering annular flanges 14 are shown as projecting downwardly and outwardly from the conical extension of the shell, and in Fig. 4, said tapering extensionis shown as provided with a plurality of circumferential, horizontally disposed flanges 15.

In. Fig. 5, the depending extension 8 of the shell is made straight .and concentric with the axis of the plug and the flanges are circumferential as in Fig. 1. With the form of the device shown in Fig. 5, the sparking terminal of the shell is formed by a pin 16 rigid with the free end of the extension 8 and the central terminal 5 is made to project farther beyond the porcelain body 4, than in the forms of shell shown in Figs. 1, 2, 3 and 4..

In the construction shown in Fig. 6, the depending extension is made straight and the sparking terminals are the same as shown in Fig. 5, but the circumferential or radial flanges 17 are made to project also somewhat downwardly, while in Fig. 7 the circumferential flanges 18 are made tapering downwardly and outwardly from the straight depending extension 6. I

Other slight changes might be made in the form and disposition of the flanges on the dependingextension of the shell without departing from the spirit of my invention orlimiting its scope, and hence I do not wish to restrict myself to the precise constructions herein set forth.

Having fully described my invention what I claim as new and desire to secure by Letters-Patent, is

1. A spark plug comprising a metallic shell having a thin annular extension to pro? ject inwardly beyond the-wall of the combustion chamber, said annular extension formed with a plurality of annular flanges projecting approximately equal distances beyond the outer face of said extension and forming a plurality of independent, annular grooves.

2. A spark plug comprising a metallic shell having a thin apron portion to project inwardly beyond the wall of the combustion chamber, said apron provided with a plurality of radiating annular flanges forming independent annular grooves between them.

3. A spark plug comprising a metallic shell having a thin apron portion to project inwardly beyond the wall of the combustion chamber, said apron provided with a plurality of circular radial flanges superposed and spaced apart forming a plurality of independent annular grooves encireling said apron.

In testimony whereof, I have signed this specification in the presence of two subscribing witnesses.

GEORGE T. SIMMONS. Witnesses:

F. L. CLEMoNs, ARTIE AT'ILESEY. 

